In recent years, there have been increasing electronics, such as a mobile terminal, having a touch screen mounted thereon. Buttons are used for an input to a typical mobile terminal in the past, and many of the users of such mobile terminal input with one hand even using the thumb. Therefore, when using a mobile terminal having a touch screen mounted thereon as well, it is a mainstream to hold the mobile terminal with one hand and to input using the thumb. When inputting using one of the thumbs in such a manner, in a case that a position of the mobile terminal held by a user (the base portion of the thumb or the like) is far from a target touch position (an input target position), a ball of the thumb sometimes gets in a state of making contact with a portion other than the target touch position. Then, this sometimes causes a position detected as a touch position (that is, a detected touch position) to be different from the target touch position.
For example, there are, in conventional technologies, input devices that solve such a gap between the target touch position and the detected touch position. The input device calculates a correction amount D/N based on a width D of a contact region and a predefined correction parameter N, and assumes coordinates obtained by adding the correction amount D/N to the center coordinates of the contact region as an operating point. In other words, the detected touch position is corrected based on the size of the contact region.
Since the size of a user's finger varies, the size of the contact region varies depending on the user even in a situation of the same holding position and input target position. The size of the contact region also varies depending on a pressing force. In other words, even in a case that the contact angle of a finger with a touch screen is same, the area of the contact region becomes larger as the pressing force becomes greater.
Accordingly, in a case that the detected touch position is uniformly corrected based only on the size of the contact region, there is a problem that it is difficult to carry out accurate correction when the size of the user's finger is different from an assumed size.
In a case of inputting with a finger of a hand different from the hand holding the mobile terminal, the finger can be made contact with a screen surface of the touch screen from a normal direction of the touch screen, so that it is preferred to fix a correction value even in a case of a different user or even in a case of a different pressing force. However, in a case of uniformly correcting a detected touch position based only on the size of the contact region, the correction value turns out to vary depending on a difference in the user or a difference in the pressing force, and thus there is a problem that it is difficult to carry out accurate correction.
Japanese Laid-open Patent Publication Nos. 2010-204812 and 2010-61372 are examples of related art.